Thanks hj - The lav trap would be over 5 feet from the tub/shower drain/vent stack - that's why I was going to do a revent. My main concern has to do with connecting the lav drain line and tub/bath drain line together before the combined line feeds into the cross wye. I spoke with the local inspector and they suggested coming out to look at what I wanted to do - it might be getting too complicated and time consuming at this point, so I may drop this enhancement.

Lee

: Without seeing your actual setup anything we suggest will be a guess, but from your description, it appears that you can connect the lavatory drain to either the toilet or tub vent riser. If it is within the allowable trap arm distance, then you would also not need a revent for it. This is assuming this is not a lower level bathroom with a toilet above it.

: : I'm remodeling a small master bathroom and am investigating adding a lavatory rough in to an alcove area on a wall adjacent to the master bathroom. I'd like to connect the lavatory drain to the tile shower/tub drain using a horziontal wye line that connects to a vertical cross tee (back to back vent/waste stack shared by the tub/shower drain in the other bathroom).

: : I can do a revent from the lav to the vent stack above the water closet that vents to the roof. The shower/tub vent is revented to this stack as well.

: : Can this be done per the UPC? I did some reading and it looks like each fixture drain line may need to be connected separately.